Love Behind the Mask.

Si Yichen, son of King Zishang, loses his entire family in a massacre on his wedding day. To seek revenge, he assumes the identity of Mu Han and gains the trust of the Eldest Princess. Meanwhile, his fiancée, Hang Anning, believing him to be dead, infiltrates the palace by swapping faces with the princess. Under the same roof, their hidden identities lead to unexpected emotions, love and vengeance become inseparable.